Transmission



z sheets-sheet 1 M. P. wlNTHl-:R

TRANsMIssI'oN ."G/ 512 (IT-3 BI March 27, 1951 Filed April 21, 1949March 27, 1951 M. P. wlNTHER 2,546'378 TRANSMISSION Filed April 21, 19493 Sheets-Sheet 2 FIGS.

March 27, 1951 M. P. wlNTHER I TRANSMISSION 3 Sheets-Sheet 3 Filed April21, 1949 Patented Mar. 27, 1951 TRANsMIssIoN Martin P. Winther, GatesMills, Ohio, assig'nor to Martin P. Winther, as trustee ApplicationApril 21, 1949, Serial No. 88,880

12 Claims. (Cl. 74-759) This invention relates to transmissions, andWith regard to certain more specific features, to improvements upon thetransmission shown in the United States patent application of myself andAnthony Winther, Serial No. 593,236, filed May 11, 1945, forTransmission, issued as Patent No. 2,540,639, dated February 6, 1951.

The invention has for its object the provision of an extra speed for thetransmission of said application without the need for the addition ofany gears. This is accomplished by providing an additional drive for theplanetary carrier of an already existent planetary gear train 'in saidtr'ansmission.l The drive for the purpose requires only an extra clutchand driving quill which not only is simpler to design than would beadditional gear trains, but is more economical to produce and is troublefree.

-` The invention comprises, in addition, means for employing the addedspeed (which is fourth speed forward) as an overdrive without producingexcessively high speeds of any existing gear. This latter feature isaccomplished by coupling the annular gear of one of the planetary geartrains shown in said application with the carrier through an overrunningclutch. This provides for the added speed without interfering with theformer operation of the transmission 'at other speeds. Other featureswill be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements ofl parts whichwill be exemplified in the structures hereinafter described, and thescope of the application of which will be indicated in the followingclaims.

In the accompanying drawings, in which one of various possibleembodiments of the invention is illustrated,

Figs. 1-5 are schematic diagrams only of pertinent torque-carrying partsinvolved in the power fiow through the transmission for first.`v``lsecond, third, fourth and reverse speeds, respectively; i

Fig. 6 is a complete schematic diagram of the parts fragmentarily shownin Figs. 1-5;

Fig. 7 is a longitudinal half section of a prac- ,tical embodiment ofthe invention;

I. Fig. 8' is an enlarged typical section taken on line 8-8 of Figs. 6and 7, illustrating the operative direction of a roller clutch orreverse-lock- Similar reference characters indicate corres spondingparts throughout the several views of the drawings.

Diagrammatic Figs. 1-5 have been placed first in' order of the drawingsso that their identifylng numbers conveniently correspond to the firstto fifth speeds, respectively, to which these figures relate.`Diagrammatic Fig. 6 integrates the showings of Figs. 1-5. Descriptionhowever will be started with the practical embodiment of the inventionrepresented by Fig. '7. Since the invention relates to internalstructural improvements,

` lowed), numeral I indicates the transmission case or frame, which isstationary and carries a rotary fly wheel 3 driven from the usual flange4 of an engine (not shown). The flywheel 3 carries a housing 5 whichrotates with it. Within the housing 5 is a magnetic-driving ring 1 whichcarries two pairs of annular electrical exctation coils 9, Il and |3,|5. In the flywheel 3 (which is also magnetic) is carried a pair ofannular excitation coils ll, |9. The stated coils are carried ingrooves, being held in place by nonmagnetic rings 2|. Each pair of coils(I, ll), (|3, |5) and (l'l, |9) is independently excited, but both coilsof each pair are excited simultaneously so as to be operative together.De.- tails of the excitation circuits will not be necessary, since it iswell known how to serve current to rotary coils in electrical machinery.It suffices to say that each pair of coils is supplied with current overone of the collector rings 23 shown on the housing 5, suitable brushesfeeding the collector rings and the coils being grounded to complete therespective circuits.

The housing 5 also carries guide pins perlpherally spaced and one ofwhich is shown at 25.

'These guide pins .slidably support driving mag.-

netic clutch plates 21 and 29, the plates being driven in a rotarymanner by the pins and being axially slidable thereon. Additional guidepins 3| are also employed for the plate 21. The pe- 'ripheries of theplates slidably fit the interior of lthe housing 5.

Between the left-hand side of plate 29 and the right-hand side of theflywheel is interposed 'aldriven clutch plate 33 of what willhereinafter be called a first power clutch O l. Between lthe right-handside of the driving plate 29 and the left-hand side of the driving ring1 is interposed a driven clutch plate 35 of what will hereinafter becalled a second power clutch 0-2.

Between the right-hand side of the driving ring 1 and the left-hand sideof the drying plate 21 is interposed a driven clutch plate 31 of whatwill hereinafter be referred to as a third power clutch C-3.

When the pair of clutch coils I1, I9 is excited, their resultingtoroidal flux fieldsfwhich mag;- netically link members', 33 and 29)'Will 'draw the plate 29 to the left, thus closing clutch C-I. When thepair of coils |3, I is excited, their resulting toroidal fiux fields(which magnetically link the members 1, 35 and 29) will draw the plate29 to the right, thus closing the clutch C--2. When the pair of coils 9,II is excited, their toroidal flux fields (whichmagnetically link themembers 1, 31 and 21)' will draw the plate '21 to the left, thus closingthe clutch In the absence of excita't'ion of the coils mentioned. plates2.1 and 29 are released and there- Spective clutches are open.

The driven plate 33 of clutch' C'--VI is' lfastene to ahub 39 whichiskeyed to a central shaftflI, supported at the left in-abearing 43andatlthe right in avpilot bearing 475. At its right-hand end the shaft4| carries a primary pinion or sun gear 40. lThe driven plate 35 offclutch -2' is fastened to a hub 41whichvis keyed to aquillV 49. Thehub G1, being ,supported in a bearing 5| Within the ring 1,V inreifectmakes the quillll supported on thatl bearing; rAt its righthand endthequill 49 is carried upon a sleeyebearing 53 around'the central shaft 4|.At this end,flthe i ing 81 surro'unding the quill '19.

be necessary since more conventional clutches or brakes aresatisfactory; except to state that when either of the members 21, 29 or1I is attracted by a fiux field, its piston effect in the casing 5 or 61tends to squeeze some of the flowable magnetic material around therespectively operative clutch plate 33, 3j5 or 31-, while at the sametime the apparent Viscosity of the material 30 is increasedmagnetically. Thus the frictional drivihg or braking effect occurs inpart through shearing of the magnetic fiuid interposed betweenthefriction surfaces. However, as stated, this type ofclutch 01'., brake issimply a refinement over vother more conventional clutches or brakesthat maybe used.

Centrally, vthe brake disc 11 is attached to a hub 19' which is keyed toa second quill 8| surrounding the first quill 189. This second quill 8Ialso carries a second hub 83, which in turn carries the driven disc '31'of the 'clutch C'- -v3. The hub 83, and thus 'also the quill Bi, areboriie upon a bearing 85 within the ring 1. At its other end, the quill8I is supported upon a bear= I At this end, the quill 8| is alsoprovided witha secondary sun gear or pinion 89. Thus it will be clearthat the quill 8|, gear 89, brake disc 11 and clutch l'plate 31 form oneintegrally rotary unit; the clutch quill carries a fiange'. 55 which isVperipherally toothed as shown at 51 for an interlocking engagement crcrown coupling engagement with inwardly directed peripheral teeth l59lof a ring BI., The ring GI is concentric With the flan'ge and the teeth'51 and V59therefore form 'a directinterlock betweenthe qui1l49 and thering to produce a permanent (1.):(1) rotary relationship. As will beshownbelow', the-ring I is integrally rotary with a lcarrier 63 of asecondary planetary gear train, The clutch C-V-2 andquill. 49 interlockwith this carrier 63 and constitute one vof the novel features of thepresent inyention. 1 At 3+1 isshown lan electric brake constituted byzamagnetic ring 65 bolted with a housingGT to the case I. Studs 59 arecarried :betweenthe housing 61 and-ring -65, a suitable number ofthesebeing spaced peripherally. Slidingaxially 'on the studs is a.magnetic brake ring -1l the peripher'y of which slidesin housing 51..vWhileth-is brakering is axially movable, it, `lik.e.the brake ring 65,is not rotary. carried in the brake ring 65 `is an zannular fieldcoil13, Lying in a suitable groove and held in place by a nonmagneticring 15. Carried lbetween the brake ,ringsand `1| is a magnetic brakedisc, 11.. When thecoil 13 is energized, the resulting toroidal magneticfield interlinks the members 55, 11 and 1 I, thereby vdrawin'g the ring1I toward the ring vlsand :closingbrake AB- -I. When the coil 13 isdeener- .gized, brake B-iI opens.

It may be mentioned at this `point vthat any `of the usual forms ofelectromagneti'c clutches are satisfactory for C-I, C-2 and 'Of-3, or anelectromagnetic brake forB-L A particularly 'satisfactory form of each.is on'e i'n which .a flexible magnetic mixture isiused such as shown atnumeral 39'. .This mixture maybe of powdered -iron with oil or grease,the Aoperation of ywhich vis disclosed in the United States patentappli- -'cation of myself andi-inthony. Winther, ;Serial No. 583,980,filed March 28, 1949., for Electromag- I W I25 and a primary carrier I21carry's'tudsfil) netic Clutch. Further description herein will not plate35, quill 49, fiange 55 and ring 6i form 'another integral rotary unit,attached tov carrier 53; and clutch plate 33', central shaft M andprimary sun gear 49' form another integral -rotary unit (see Fig. 6). vi

The carrier 63 is an assembly composed ofa supporting Spider rotarybetween bearings93' and 95 within the ring 65 and around the quill 8|,respectively; a cylindric brake drum 91; and a supporting Spider 99rotary between bearings IOI and I02. Operative on thev brake drum "91'isva releasable brake bandxsystem I1 which, with the drum 91, forms asecond and releasable'brake B-2. This may be any. suitable band bralre'.

Ke'yedfto an extension quill 199 of the fspider 99 is the inner race I II of a reVerse-locking brake .I'I3 (Fig. '9). The o uter race II`5 lofthis brake is'fixed in the case I and the arrange'ment Vis such that the'inner race Ili may rot'atrefl clo'ckwii's'e (Viewed from Athe left Vendfo`f the machine in Fig. 7 but may not rotate 'anticlo'cl;wise,fbeingthen anchored with respect to the case I. In other Words, the .carrierE3 'can rot'ate clockwi'se o nly, and if an attempt is made 'to rotateit 'anticlockwise, it will lock withrespect to the Vcase I. Theessentials of such a r'oller brake are shown inFg. 9, wherein numerals'112 indicate the braking members and numerals .I I and III6 representthe one-way braking surfaces. Other 'equivalent reverse-locking brakesmay be used. They are sometimes referred to in the literatureas one-way,overrunni'ngor freewheeling clutch'e's'. f

The ring 6I land. Spider II are connected bjy studs 153 at spacedperipheral interr'vals. Each vstud I03 carries a secondary planetarygea'lif which centrally meshes with the secondaryA 'sun gear 89. Eachplanetary gear E meshs'out- Wardly With the interior teeth II'2I of. anVannular or secondary ring gear Ill.l Gear Ill'l is carried by theprimary carrier 121.. This ringge'ar Vi I`1 .is rotary in the carrier63, being supported infa bearing I I9 on the inside of the carrier.'Theinternal teeth w |2I mesh with outwardl'y' extending teeth I23 of a,ring 125. The ring T25 and animthey are locked forv (1):(1')'v rotation.The ring upon which' are primary planetary gears 131 meshing centrallywith the primary sun gear 49. These gears 131 mesh outwardly withinternal teeth 133 of a primary internal ring gear 135 forming part of areverse-locking reactor ring 13'1. Ring 13'1 is carried upon a bearing139 and carries the internal race 141 of a second one-way overrunning orfreewheeling clutch 143 illustrated also in Fig. 8. The outer race 145of the overrunning clutch 143 is fixed in the secondary carrier 63. Theclutch 143 is such that, relative to the carrier 63, the reactor ring13'1 may move only clockwise (Fig. 8). Any attempt to turn the reactorring 13'1 anticlockwise relative to the secondary carrier 63 results inthe two members 13'1 and 63 being locked together. These points areillustrated in Fig. 8, wherein numerals 14'1 represent the lookingrollers and numerals 146 and 1413 the looking surfaces. Other equivalentreverse-locking brakes overrunning or one-way clutches may be used. Theprimary carrier 12? is attaohed within the enlarged end 14'5 of thedriven shaft 149 of the transmission, the latter being coupled to theload to be driven.

It will be understood in respect to the gears 195 and 131, that only oneeach is shown in the half section of Fig. 7, but that a plurality ofeach of these is arranged at spaced intervals around Vthe transmissionas is usual for balance in the case of planetary gear trains. Forexample, two or three,. or more, each may be used at 180, 120 et cetera.

Operation can be traced from the power fiow diagrams (Figs. 1-5) and thefollowing power flow chart, in which letter` O indicates an open orreleased condition, the letter C a closed condition, and a dashrepresents either an open, a closed or an indiiferent condition. Thelast line specifies the typical speed ratios for the various speedslisted.

. Power flow chart In all the Figs. l-5, the curled arrows A representengine speed and the curled arrows C driven speed. All of the curledarrows A are of the same size and the relative sizes shown for C' in therespective figures qualitatively indicate the Velocity' of the drivenshaft 149.l

In Figs. 1-5, cross hatching indicates that under the conditionsinclicated, the parts hatched are fixed -at the moment, relative to thecase, which latter is a frame of reference and hatched in all of Figs.1-6.

First or low speed (Figs. 1 and 7) Coils 11 and 19 are excited, thusdrawing over the clutch plate 29 andclosing power clutch O which placesin rotation the central shaft 41 and .primary sun gear 41). Assume therotation to be clockwise, viewed from the left, as shown by the arrow A.This will tend to turn the planetary gears131. anticlockwise, Thesethentend to turn the internal gear anticlockwise, along 'with' the reactorring 131. This anticlockwise rotation locks the freewheeling clutch 143,which tends to turn the primary carrier 63 anticlockwise which in turnlooks the reverse-looking brake 1 13 which becomes the fixed fulcrum ofthe system. The result is that the internal gear 135 cannot moveanticlockwise and the pinions 131 must roll around the internal gear135, thus foroing the primary carrier 12'1 olookwise at reduced speed.Since the primary carrier 12'1 drives the shaft l1119, the latter isdriven at reducedspeed in the ratio of (3) :(1) relative to the flywheel3. As the chart shows, the clutches C-2, C-3 and brakes B 1 and B-Z areat this time released, so that there are no inconsistent movementsrequired of the.. parts shown in Fig. 1 by the parts thatar not shown.

Second speed (Fig 2) Clutch C-I remains closed aid brake B--`1 is set orlocked. Again shaft 41 and primary sun gear 40 rotate clockwise as forfirst speed, but the fulcrum of the system transfers from the clutch 113 to the now fixed gear 89. The resulting operation includes movementof the secondary carrier 63 clockwise which opens brake 113, the clutch143 remaining closed. Thus the action is like that in low gear (Fig. 1)except that there is added the motion induced by carrier 63 in rollinggears on the stationary sun gear 89. These, through gear 1 1'1, advancethe motion of carrier 12'1 and shaft 149 over what it is under firstspeed conditions. The resulting speed ratio of 41 to 149 is (1.5) :(l).

Third speed (Fg. 3)

Fourth speed or overdrve (Fig. 4)

In this case, clutch C-2 is closed, causing r'o'- tation of the quill49. Brake B 1 is again locked, which locks gear 89. Quill 49 rotates thesecondary carrier 63. Thus the secondary planetary gears 1115 roll onthe stationary sun gear 89, driving ahead the secondary annular gear11'1. This drives ahead the primary carrier 12'1, which drives the shaft149 at a ratio of approximately (.'72) :(l). In other words, the shaft149 rotates faster than the clutch C-Z which consti'- tutes overdrive.tions, the forwardly rotating secondary carrie 63 opens bral-:e 1 13.

Reverse speed (Fig. 5)

Clutch C'--3 is closed and brake B-2 is locked. Thus C-3 drives thequill 81. The secondary carrier 63 being fixed in position by the brakeB 2, fixes the axes of the gears 1115.v Thus clockwise rotation of thequill 81 drives gear 8-9 clockwise, driving gears 105- anticlockwise,which in turn drive the gear 11'1 anticlookwise. The result is that theprimary carrier 12'1 drives the shaft 149 anticlockwise, as shown, at aspeed ratio of approximately (3);(1). Under these conditions there is noplanetary action.

Itwill be understoodjntheabove that. EigS-.l-,

Under these Operating condibeing diagrammatic, do not portray actualgear diameters.. Eig. 'Z' illustrates a practical set of relationshipsbetween gear diameters.V It will also be understood in connection withFigs. 1-5 that themissing parts are not necessary to the operationsconnected with the speeds discussed.

From the above, the advantages of the invention will be clear. Simply byproviding the additional clutch -2 With a direct connection to. thesecondary carrier 63, the additional fourth speed or overdrive isobtained without the addition of any gears to the construction shown insaid Patent No. 2,540,639. Moreover, instead of connecting gear |3directly to the secondary-carrier 63 (as in said Patent No. 1540539) andby connecting it thereto through the overrunning clutch |43 (as herein),the overdrive of Fg. 4 herein may be obtained without excessively highspeed forward of the shaft 4|, which is then out of action. Thusexcessive idling speeds of nonconnected gears are avoided underoverdrive conditions. Of course this problem did not present itself insaid Patent No. 2,540,639 because there is no overdrive therein. Thislast-mentioned feature of' the inventon may be summed up in thestatement that provision has been made to let the primary ring gear ifioat, except When it is required for driving.

Although the member 143 has above been referred to as an overrunningclutch and freewheeling clutch, it will be understood that it may alsobe considered to be a reverse-locking brake in the sense that it permitsforward motion of one member relative to another but looks the onemember against reverse movement With respect to the other.

Note is to be taken of the fact that in the aplpended claims clutch C-iis referred to as a first clutch; (3-3 as a second clutch; andv clutch0,-2 as a third clutch.

In view of the above, it will be seen that the Hseveral objects of theinvention are achieved and driven member; said train including a primaryplanetary gear, a carrier therefor, a primary sun gear driven by saidfirst clutch :and meshing with the primary .planetary gear, and aprimary ring :gear also meshing with said primary planetary gear; asecond clutch adapted to be driven by the driving member, a secondarygear train including a secondary carrier supporting-a secondaryplanetary gear, a secondary sun gear adapted to be driven by said secondclutch and meshing with the secondary planetary gear, and a secondaryring gear also meshing with said secondary planetary gearl and carriedby the primary carrier; and 'a third clutch directly connecting saiddriving member with said secondary carrier, said primary carrier andsecondary ring gear being connected to said driven member.

2. A transmission comprising a frame, a driv- "ing member, a. drivenmember, a first clutch driven by the driving member, a primary planetarygear train connecting the driving and driven members including a.primary carrier attahedtc the driven member and suppqrtins a 12121111.planetary gear of. said planetary train, a. primary sun gear driven by.said firstclutch andl meshing with the primary planetary gear, and aprimary ring gear also meshingl With said primary planetary gear; abrake;` a second clutch adapted to be driven by the driving member, asecondaryl plane-` tary gear train including a secondary carrier sup,-porting a secondary planetary gear, a secondary sun gear adapted to bedriven by` said second clutch or be locked against rotation by saidbrake and meshing with the secondary planetary gear.. a secondary ringgear also meshing with said sec,- ondary planetary gear and carried bythe .primary carrier, a second brake- OH progressively looking` saidsecondary sun gear against rotation,; a third clutch adapted directly toconnect said (hiring; memberv With said secondary carrier; and a re.-Verse-lockingv brake connecting the secondarycarrier with the frame toprevent relative movement thereof, said primary carrier and said, 8.9G-ondary ring gear being interconnected.

3. A transmission comprisng a frame, a driving member, a driven member,a first clutch driven by the driving member, a primary planetary geartrain connecting the driving and driven members including a primary'carrier attached to the driven member and supporting a primary planetarygear, a primary sun gear driven by said first clutch and meshing withthe primary planetary gear, and a primary ring gear also. meshing Withsaid primary planetary gear; a second clutch adapted to be driven by'the driving member, a. secondary planetary gear train includingr asecondary carrier supporting a secondary planetary gear, a secondary sungear adapted to be driven by said second clutch and meshing with the secondary planetary gear, and a secondary ring gear also meshing with saidsecondary planetary gear and carried by the primary carrier; a brake forlocking said secondary sun gear against rotation, a third clutchdirectly connecting said driving member with said secondary carrier; areverselocking brake connecting the secondary carrier with the frame tolimit rotation of said secondary carrier to a direct-,ion with that ofSaid driving member; and an overrunning clutch connecting said primaryring gear with the secondary carrier for unitary rotation, said primarycarrierand said secondary ring gear being interconnected.

4. A transmission comprising a frame, a driving member, a driven member,a first clutch driven by the driving member, a primary planetary geartrain connecting the clutch and the driven member; said train includinga primary carrier attached to the driven member and sup.-

porting a primary planetary gear, a primary sun gear driven by saidfirst clutch and meshing with the primary planetary gear, and a primaryring gear also meshing with said primary planetary gear; a second clutchadapted to be driven by the driving member, a secondary planetary geartrain including a secondary carrier supporting a secondary planetarygear, a secondary sun gear adapted to be driven by said second clutchand meshing with the secondary planetary gear, and a secondary ring gearalso meshing With said secondary planetary gear and carried by theprimary carrier; a brake for restraining said secondary sun gear fromrotation, and a third clutch directly connecting said driving memberwith said secondary carrier, said primary carrier and said secondaryring gear being interconnected.

5. A transmission comprising a frame, a drive' acc-8,878

ing member, za drivenmember, a; first clutch driven by the drivingmembena primary plane- 'tary gear train conne'ctng the clutch and thedriven member; said train including a primary carrier attached to thedriven member' and supporting a primary planetary gear, a primary sungear driven by said first clutch and meshing with the primary planetarygear, and a primaryring gear also meshing with said primary planetarygear; a second clutch adapted to be driven by the driving member, asecondary planetary gear train including a secondary carrier supportinga secondary planetary gear, a secondary sun gear adapted to be driven bysaid second clutch and meshing With the secondary planetary gear, and asecondary ring gear also meshing With said secondary planetary gear andcarried by the primary carrier; a brake adapted to restrain saidsecondary sun gear against rotation, a third clutch directly connectingsaid driving member With said secondary carrier, and a second brake forconnecting the secondary carrier with the frame to prevent relativemovement thereof, said primary carrier and said secondary ring gearbeing interconnected.

6. A transmission comprising a frame, a driving member, a driven member,a first clutch driven by the driving member, a primary planetary geartrain connecting the clutch and driven member; said train including aprimary carrier attached to the driven member and supporting a primaryplanetary gear, a primary sun gear driven by said first clutch andmeshing with the primary planetary gear, and a primary ring gear alsomeshing with said primary planetary gear; a second clutch adapted to bedriven by the driving member, a secondary planetary gear train includinga secondary carrier supporting a secondary planetary gear, a secondarysun gear adapted to be driven by said second clutch and meshing with thesecondary planetary gear, and a secondary ring gear also meshing withsaid secondary planetary gear and carried by the primary carrier; abrake for selectively looking said secondary sun gear against rotation,a third clutch directly connecting said driving member With saidsecondary carrier, a reverse-locking brake connecting the secondarycarrier with the frame to limit rotation of said secondary carrier to 1adirection with that of said driving member, a brake for looking saidsecondary carrier independently of said reverse-locking brake, and anoverrunning clutch connecting said primary ring gear With the secondarycarrier for unitary rotation, said primary carrier and said secondaryring gear being interconnected.

7. A transmission adapted to be driven by a prime mover comprising aframe, primary and secondary planetary gear trains; each train includinga sun gear, a planetary gear, a carrier for its planetary gear, and aring gear meshing with its planetary gear; a releasable driving clutchfor each of said sun gears adapted to drive them indenendently ortogether from said prime mover, a third individually releasable clutchadapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier and the secondaryring gear, and a releasable brake for restraining rotation of said sungear 'in the secondary planetary train.

8. A transmission adapted to be driven by a prime mover comprising aframe, primary and secondary planetary gear trains; each train includinga"sun gear, a planetary gear, a carrier for its planetary gear, and aringgarmeshing with Vits planetary gear; a releasable driving, clutchfor each of said sunl gears adapted to drive them independently ortogether from said prime mover, a third individually releasable clutch?adapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier and the secondaryring gear, a brake for restraining'rotation of the sun gear inthesecondary gear train, and a brake for selectively preventing rotation ofthe secondary planetary carrier.

9. A transmi'ssion for a prime mover comprising a frame, primary andsecondary planetary gear trains; each train including a sun gear, aplanetary gear, a carrier for the planetary gear, and a ring gear; aclutch for each of said sun gears adapted to drive them independently ortogether from said prime mover, a third individually operable clutchadapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier and the secondaryring gear, a brake for restraining rotation of said sun gear in thesecondary gear train, a brake for selectively preventing rotation of thesecondary planetary carrier, and an overrunning Vclutch between saidsecondary carrier and said ring gear in the primary gear train adaptedto lock this carrier and ring gear for unitary movement.

10. A transmission for a prime mover comprising a frame, primary andsecondary planetary gear trains; each train including a sun gear, aplanetary gear, a carrier for the planetary gear, and a ring gear; aclutch for each of said sun gears adapted to drive themindependently ortogether from said prime mover, a third individually operable clutchadapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier and the secondaryring gear, a brake for restraining rotation of said sun gear in thesecondary planetary train, and a one-way reverselocking brake adapted tolimit rotation of said secondary carrier in a direction With that ofsaid clutches.

11. A transmission for a prime mover comprising a frame, primary andsecondary planetary gear trains; each train including a sun gear, aplanetary gear, a carrier for the planetary gear, and a ring gear; aclutch for each of said sun gears adapted to drive them independently ortogether from said prime mover, a third individually operable clutchadapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier and to thesecondary ring gear, a brake for restraining rotation of said sun gearin the secondary planetary train, a one-way reverselocking brake for thesecondary carrier adapted to limit rotation thereof in a direction withthat of the clutches, and a second brake for preventing rotation of saidsecondary carrier.

12. A transmission for a prime mover comprising a frame, primary andsecondary planetary gear trains; each ,train including a sun gear, aplanetary gear, a carrier for the planetary gear, and a ringgear; aclutch for each of said sun gears adapted to drive them independently ortogether from said prime mover, a third individually operable clutchadapted to drive the carrier of said secondary train from said primemover, a driven shaft connected to the primary carrier andV thesecondary ring gear, a brake for restraining rotation of said sun gearin the sec-

